Early onset hearing loss can impose consequential delays in communication and psychosocial development on the developing child. An immediate and obvious effect of heating loss in the young child is a deficit in the perception and production of speech. Although standardized audiometric procedures are able to describe the presence and degree of hearing loss, there are essentially no clinical measures available to assess speech perception abilities in infants as they mature. The inability to assess these skills in infants and toddlers can potentially cause erroneous decisions to be made regarding intervention. The proposed investigation focuses on auditory-perceptual development and the emergence of spoken language in the young hearing-impaired child. The means by which to accomplish this objective require the development and refinement of new behavioral assessment tools to measure speech perception in children between the ages of 6 months and 5 years. Longitudinal and cross-sectional studies will be conducted using this test battery to address the following four specific aims: 1) to ascertain the extent to which assessment task contributes to between- and within-subject variability on measures of auditory speech perception; 2) to measure changes over time in auditory speech perception performance as a function of chronological age, assessment task, auditory status, and sensory assistance; 3) to investigate the relationship between speech recognition and linguistic / cognitive variables in young developing children with hearing loss; and, 4) to describe and measure the contributions of maternal involvement to performance on tasks of language and speech perception in hearing-impaired young children, and to validate parent report as a tool for assessing language development in this population. In addressing the aims of this five-year investigation, the auditory factors and their interrelationships that underlie the development of spoken language competence in young hearing-impaired children will be defined. Auditory-perceptual development will be measured and tracked in children with normal and impaired hearing using a variety of tasks. The results will be analyzed to explain and model auditory perceptual development in terms of multiple contributing variables and their interactions.